Product or categories explorer hidden

with Joomla 2.5.3 and Hikashop 1.5.7_2012-03-22 the product or category explorer is empty , I have tried to change the admin template or the browser but it is the same

screen shot --> www.urpix.fr/files/gwlmz2h0eyu4jf5xdxx.jpg

and it is impossible to add a menu or module hikashop , in the popup the categories are hidden

thank you

and this morning

I have updated for com_hikashop_business_1.5.7_2012-03-23 and it works